1. Field of the Invention
The present invention relates to a roller device for use in a conveyor or the like apparatus and a method of making the roller device, and more particularly relates to the roller device whose characteristic feature resides in a structure of securing to a roller body a fixture that is accommodated therein wholly or partially.
2. Related Art
Various types of free rollers and/or motor-installed rollers have been employed to construct the conventional conveyors or the like apparatuses. Each free roller has comprised a roller body formed as a round cylinder supported by and rotating about a shaft, and each motor-installed roller has comprised a motor and a reducer both installed in the roller body.
In these prior art free rollers and motor-installed rollers, fixtures or closures for closing end openings of each roller body, as well as bearings or other constituent parts, have been fixed on or in the roller body. Usually, adhesives, set-screws, grooved pins, spring pins or the like fastening members have been used to secure such fixtures or parts to said roller body.
An example of the prior art structures is disclosed in the Japan Patent Laying-Open Gazette No. 6-171730. In this case, a fixing ring intervenes between the roller body and the fixture closing the open end thereof. A set-screw will be tightened sideways through a cap in order to firmly consolidate the fixture with said roller body in a wedge-like manner.
Arrays of these free rollers and/or motor-installed rollers are often used to transport any articles, goods or materials, suffering from mechanical vibration and shocks while they are transporting the articles. It has been observed often that holes or apertures for insertion of those set-screws or pins would possibly be widened gradually, loosening them and causing them to slip off at worst. In such an event, the roller bodies would no longer rotate smoothly, thus failing to transport the goods in an orderly manner.
If such set-screws or the like threaded fasteners are used for the described purpose, then those roller bodies and fixtures must be threaded not easily. A relatively complicated structure as proposed in the Gazette No. 6-171730 will render its assembling works very intricate to raise manufacture cost.
An object of the present invention is to provide such a roller device that its fixture such as a closure or bearing is easily secured to its roller body with use of a fastening member, lest any vibration or other mechanical stress transmitted or imparted to the roller device should cause the fastening member to slip off.
A roller device provided herein to achieve this object may comprise a roller body, a fixture accommodated at least in part in the roller body and secured thereto, and a fastener fixedly connecting a periphery of the fixture to a periphery of the roller body. The fastener comprises at least one transverse key driven in transverse apertures that are formed in the portions of the peripheries crosswise to an axis of the roller body. The transverse key is composed of a columnar solid portion and a cylindrical collapsible foot continuing therefrom, such that a thrust applied axially of the key to the solid portion will expand the collapsible food radially and outwards so as to inhibit the key from moving axially thereof, whereby the solid portion is retained in place to prevent the fixture from moving relative to the roller body.
When assembling this roller device, the at least one key as the fastener will be placed in the aperture and then struck transversely of the roller body. As a result, the cylindrical collapsible foot of the key will collapse so as to form a bulged flash. This flash hooks the rim of said transverse aperture so that the fixture will now be retained in the roller body much more strongly as compared with the prior structures, and the fastener itself will surely be protected from slipping off.
Such a fastener will never loosen itself, once its collapsible foot has deformed itself inside the roller body, even if any noticeable vibration is produced during a subsequent operation of this roller device. Owing to presence of the un-collapsed solid portion, the key as the fastener will reliably prevent displacement of the roller body relative to the fixture easily and surely consolidated therewith.
From another aspect of the invention, it provides a roller device comprising a roller body, a fixture accommodated at least in part in the roller body and secured thereto, and a fastener fixedly connecting the fixture to a periphery of the roller body. The fastener comprises at least one transverse key and at least one anvil member combined therewith. The key is composed of a columnar solid portion and a cylindrical collapsible foot continuing therefrom, such that a thrust applied axially of the key to the solid portion will expand the collapsible foot, with the solid portion being retained in place to prevent the fixture from moving relative to the roller body. The anvil member is shaped such that the thrust applied to the solid portion will force this member into the collapsible foot so that this foot is expanded radially and outwards.
When assembling this roller device, the at least one key as the fastener will be placed in the aperture and then struck transversely of the roller body. The anvil member thus entering the collapsible foot will serve to surely collapse it radially within the roller body so as to form a dilated foot. Such a dilated foot will retain the fixture in place in the roller body much more strongly as compared with the prior structures, and the fastener itself will surely be protected from slipping off.
Also in this case, the fastener will never loosen itself after its collapsible foot has been deformed inside the roller body, even if any notice able vibration is produced during operation of this roller device. Owing to the presence of the solid portion un-collapsed, the key as the fastener will reliably prevent the roller body from being displaced relative to the fixture having easily and surely been consolidated therewith.
Preferably, the collapsible foot of the key incorporated in the roller device may be a hollow portion of said key so that a weak force initially applied thereto from the outside does suffice well to deform said foot. Such a hollow foot will make it easier to more surely fix the fixture to the roller body.
Two or more fasteners may preferably be arranged at intervals around the roller body that constitutes the roller device of the invention.
External forces such as vibration acting on the periphery of roller device will be distributed to the fasteners. These fasteners are more surely protected from loosening themselves, with the apertures holding them becoming less likely to be deformed.
Preferably, each aperture formed in the fixture to receive the fastener may communicate with a recess that also is formed in the fixture so as to extend crosswise to a direction in which the fastener is inserted.
In this case, the fastener""s collapsible foot will be guided to deform itself along the surface of such a recess in a direction crosswise to the direction in which the fastener is being struck. The recess extending in a direction crosswise to the direction in which said fastener is inserted will be effective to much surely prevent the slipping off of the fastener.
On the other hand, the columnar solid portion of the key as the fastener may preferably penetrate both the aligned portions of said roller body and fixture.
The fixture will reliably be protected from displacement relative to the roller body, not only in axial direction but also in circumferential direction thereof.
The anvil member also employable in the roller device of the invention may have a pointed top, an enlarged bottom, and a tapered region smoothly transferring from the top to the bottom. The top is of an outer diameter smaller than the inner diameter of the key""s collapsible foot, with the bottom having an outer diameter larger than said inner diameter.
In this case, a relatively weak external force will suffice to force the anvil member to enter and smoothly expand the collapsible foot along the tapered region of such an anvil member. Consequently, deformation of the key will be rendered much smoother and surer, more firmly setting the fixture in place in the roller body.
The roller device described above may comprise a motor installed in the roller body so that a torque necessary for this body to rotate will be transmitted thereto from the motor.
Although the roller body and fixture will be subjected to vibration caused by such a motor, the fastener whose collapsible foot has been deformed will neither loosen itself nor slip off to cause any unsmooth rotation of said roller body.
From still another aspect, the present invention provides a method of making a roller device that comprises a roller body, a fixture accommodated at least in part in the roller body and secured thereto, and a fastener fixedly connecting a periphery of the fixture to a periphery of the roller body, with the fastener comprising at least one transverse key that is composed of a columnar solid portion and a cylindrical collapsible foot continuing therefrom. The key is designed such that a thrust applied axially of the key to the solid portion will expand the collapsible foot radially and outwards so as to inhibit the key from moving axially thereof, and the solid portion is retained in place to prevent the fixture from moving relative to the roller body. The method of making such a roller device may comprise the step of placing the fixture in the roller body so as to take a predetermined position therein, and the step of finally striking the fastener axially thereof so as to deform its collapsible foot radially and outwards, after inserting the fastener into transverse apertures formed in portions of the peripheries crosswise to an axis of the roller body.
When assembling this roller device by this method, the at least one key as the fastener will be placed in the apertures and then struck transversely of the roller body. As a result, the cylindrical collapsible foot of the key will collapse so as not to slip off. Thus, the fastener and the fixture will now be retained in place much more strongly as compared with the prior structures, lest they should slip off even under a vibrational condition during transportation of articles.
Preferably, the collapsible foot of the key as the fastener used in the present method to assemble the roller device may be a hollow portion of said key.
In this case, a weak force initially applied thereto from the outside suffices well to deform said foot. Such a hollow foot will make it easier to more surely fix the fixture to the roller body.
Preferably, each aperture formed in the fixture to receive the fastener used in the method may communicate with a recess that is also formed in the fixture so as to extend crosswise to a direction in which the fastener is inserted. At the step of striking the fastener in this case, the fastener""s collapsible foot will be guided to deform itself along the surface of such a recess and into a close contact with this surface, when the fastener is struck axially thereof.
The recess along which the collapsible foot of the key is forced to deform itself will be effective to much surely prevent the slipping off of the fastener and fixture even under any vibrational condition.
The fastener used in the present method may comprise an anvil member in addition to the key as described above. The anvil member can be pressed partially or wholly into the collapsible foot, at the step of striking the fastener axially thereof. In this way, the collapsible foot will make its smooth dilation radially and outwards.
Reliable radial deformation of the collapsible foot is thus ensured by virtue of such an anvil member, whereby a much easier and surer consolidation of the roller body and fixture into the roller device is afforded by such a mode of the present method.
The anvil member used herein to make the roller device may have a pointed top to be disposed inside the key, an enlarged bottom to be disposed outside the key, and a tapered region smoothly transferring from the top to the bottom. The top of this anvil member is of an outer diameter smaller than the inner diameter of the key""s collapsible foot, with the bottom having an outer diameter larger than said inner diameter. Therefore, such a top will lead this anvil member into the collapsible foot so as to dilate it radially and outwards, at the step of striking the fastener.
In this case, a relatively weak external force will suffice to force the anvil member to enter and smoothly and gently expand the collapsible foot along the tapered region and bottom of such an anvil member. Consequently, deformation of the key will be rendered much smoother and surer, more firmly setting the fixture in place in the roller body.
Two or more fasteners may preferably be arranged at intervals around the roller body that constitutes the roller device that will be made by the present method.
External forces such as vibration acting on the periphery of roller will be distributed throughout the fasteners. These fasteners are more surely protected from loosening themselves, with the apertures holding them becoming less likely to be deformed.
On the other hand, the columnar solid portion of t he key as the fastener used in the present method may preferably penetrate both the aligned portions of said roller body and fixture.
The fixture will reliably be protected from displacement relative to the roller body, even under any vibrational condition.
The present method of making a roller device described above may further comprise the step of installing in the roller body an electric motor serving as an actuator for driving this body to rotate.
Although the roller body and fixture constituting the roller device will be subjected to vibration causes by such a motor, the fastener whose collapsible foot will have been deformed during execution of this method will however neither loosen itself nor slip off, by virtue of the deformed collapsible portion fixing the fastener in place. Thus, notwithstanding the motor as an actuator installed in said roller body, this body will not be displaced relative to the during operation of said roller device.